I've had several friends break their packs by flipping them over their heads. In fact, one friend had a shoulder straps break on day one of our Philmont trek years ago.
The way I put my pack on, as a right-handed person, is to hold the haul loop in my left had and the right shoulder strap in my right hand. I then lift it up and around the right side of my body while sliding my right and then left arms through the straps. This way most of the weight is held by the haul loop until right before I slip my left arm through. It works for me from 20lbs to 60lbs.